Process for resolving petroleum emulsions



atented Feb. 11, 1941 PATENT ornca PROCESS FOR RESOLVING PETROLEUMEMULSION S Melvin De Groote, University City, Mo., assignor, by mesneassignments, to Petrolite Corporation, Ltd., a corporation of DelawareNo Drawing. Application February 20, 1939,

Serial No. 257,333

l Claims.

ment of emulsions of mineral oil and water, such as petroleum emulsions,for the purpose of separating the oil from the water, and has for itsmain object to provide a novel process for resolving or breakingpetroleum emulsions of the water-in-oil type.

Petroleum sulfonic acids are produced from a wide variety of petroleumdistillates or petroleum fractions, and in some instances, they areproduced'from the crude petroleum itself. When produced from crudepetroleum itself, it is customary to ise crude oil of the naphthenetype, crude oil of the paraflin type, crude oil of the asphaltic type,and mixtures of said three different types of crude oil.

The art of refining petroleum crude or various fractions, using sulfuricacid of various strengths, as well as monohydrate and fuming acid, is awell known procedure. In such conventional refining procedure, petroleumsulfonic acids have been produced as by-products. For instance, inremoving the olefinic components, it has been common practice to usesulfuric acid, so as to polymerize the olefines, or convert them intosulfonic acids which are subsequently removed. Likewise, in theproduction of white oil, or highly refined lubricating oils, it has beencustomary to treat with fuming sulfuric acid, so as to eliminate certainundesirable components.

In recent years, certain mineral oil fractions have been treated withsulfuric acid, with the primary object of producing petroleum sulfonicacids, and in such procedure, the petroleum sulfonic acids representedthe primary objects of reaction, rather than concomitant by-products.

Petroleum sulfonic acid, regardless of whether derived as the principalproduct of reaction, or as a by-product, canbedivided into the generalproducts, to wit, green acid or acids, and mahogany acid or acids. Thegreen acids are characterized by being water-soluble 0r dispersible. Inother words, they form either true solutions or sols. For purpose ofconvenience, they will be herein referred to as water-soluble, withoutany effort to indicate whether the solution is molecular or colloidal innature. The greenacids, as indicated by their name, frequently give anaqueous solution having a dark green or greygreen appearance. Theygenerally appear as a component of the acid draw-ofi, and do not remainbehind dissolved in the oil fraction, which has been subjected tosulfuric acid treatment.

The green acids are not soluble in oil, even when,

substantially anhydrous, and certainly are not This invention relatesprimarily to the treatsoluble in oil when they contain as much as 15% ofwater. Similarly, their salts obtained by neutralizing the green acidswith a strong solution of caustic soda, caustic potash, or ammonia, arenot oil-soluble. For convenience of classifl- 5 cation, the ammoniumsalt will be considered as an alkali salt.

In contradistinction to the hydrophile green acids, there occurs, as inthe manufacture of medicinal white oil, the oil soluble type, or the 10mahogany acids. These mahogany acids are characterized by being solublein oil, especially when anhydrous, and being soluble in oil, even ifthey contain some dissolved water. Some of the mahogany acids also showlimited hydro- 18 philic properties, to the extent that either somewater can be dissolved in the acids, or they, in turn, may dissolve tosome extent in water. In some instances their salts, such as the sodium,ammonium, or potassium salt, will dissolve in 20 water to give acolloidal sol. However, regardless of the presence of any hydrophilicproperties whatsoever, they always have a characteristic hydrophobeproperty, as indicated by the 'fact that the substantially anhydrousform, for in- 25 stance, their alkali salts containing 5-12% water, willdissolve in oil. This clearly disti u shes them from the green acidspreviously referred to, because the green acids in similar formcontaining the same amount of water, for example, will not dissolve inoil. The green acids as such are essentially hydrophilic andnon-hydrophobic in character.

The utility of the mahogany acids in various arts has been enhanced byincreasing their water 35 solubility; for instance, converting themahogany acids into hydroxy alkylamine salts. On the other hand, as faras I am aware, no valuable product of commerce has resulted fromdecreasing the water solubility of themahogany acids 40 by the additionof some oil soluble basic amine, such as, for example, trlamylamine. Thetriamylamine salts of mahogany acids, for example, are completely devoidof any solubility in water, which the alkali salts may have exhibited,and show, as would be expected, an increased solubility in hydrophobesolvents.

Green acids are hydrophile in character, as previously stated. Theirhydrophile character has been increased by neutralization with mate- 5rials such as triethanolamine and the like. Such green acid salts havingenhanced water solubility, as compared with the ordinary alkali salts,have found application in certain arts.

I have found that if green acids, that is, the s oil-insoluble type, areneutralized with an alkylamine of the kind hereinafter described, so asto produce a water-insoluble product, the resulting material, eventhough it does not exhibit any marked oil solubility, especially when itcontains 5-10% of water, still has pronounced value as a demulsifier foroil field emulsions, either when used alone, or when used in conjunctionwith other known demulsifying agents. I employ alkylamines of the kindwhich contain at least one propyl radical and contain no other radicalin which there are more than three carbon atoms present. Attention isdirected to my co-pending application for patent, Serial No. 193,063,filed February 28, 1938, now Patent 2,153,745. I have also found thatsometimes such an amine salt of green acids will mix in with ahydrophobe material and a hydrophile material, so as to produce ahomogeneous mixture. The effectiveness of the above described materialor composition of matter as a demulsifying agent for oil field emulsionsappears to be related to some factor other than its solubilitycharacteristics.

The new composition of matter then which I use as the demulsifier in myimproved process for resolving petroleum emulsions, is represented bythe described alkylamine salts of hydrophilic nonhydrophobic greenpetroleum acids, as exemplified by the dipropylamine salt. The!manufacture of said new composition of matter involves nothing more orless than neutralizing the selected petroleum sulfonic acid with asuitable amine until neutral to methyl orange indicator, or othersuitable indicator. For purpose of convenience, I prefer that theselected petroleum sulfonic acid contains not over 15% of water. It isunderstood, of course, that the conventional procedure employing doubledecomposition, instead of direct neutralization, can be employed in themanufacture of my new material or composition of matter. For instance,the sodium salt of the selected petroleum sulfonic acid can be dissolvedin alcohol and the amine hydrochloride added, so that sodium chloridewill precipitate. After filtering oif the precipitated sodium chloride,the alcohol can be evaporated and the amine salt recovered. If desired,a mixture of amines, instead of a single amine, may be employed.

There are a large number of alkylamines available which arecharacterized by having present at least one propyl radical and no otherradical having more than three carbon atoms. Suitable examples includemonopropylamine, dipropylamine,-tripropylamine, ethyldipropylamine,methyldipropylamine, dimethylpropylamine, diethylpropylamine,dipropylethanolamine, etc.

There is no objection to using an alkylamine of the kind described, eventhough a hydroxy alkyl radical is present, provided that neutralizationof the green acids yields a water-insoluble salt. For instance, as hasbeen pointed out, one might employ dipropylethanolamine ordipropylpropanolamine. Similarly, one might employdipropylpropanolamine, or an amine containing a glyceryl radical, suchas dipropylglycerylamine, provided that the salt derived from the greenacids was water-insoluble.

It may be well to point out that hydrophile nonhydrophobe petroleumsulfonlc acid or acids of the green acid type vary somewhat; forinstance, the molecular weight may vary within the range of 350-500, orthereabouts. Naturally, these petroleum sulfonic acids may carry somepolymerized olefines, free hydrocarbons, or the like, or may even carrya bit of naphthenic acids which represent carboxylated non-sulfonatedpetroleum acids. As previously stated, these materials are well knowncommercial products and are available in the open market, either in theform of the acid itself, or in the form of a salt.

In the claims the amine is referred to as basic to indicate that thebasicity is in the neighborhood of that of ammonia or triethanolamine.In some instances, the basicity may be somewhat greater, or perhapsslightly less. Basicity is insured in amines of the kind described,because they do not have present an aryl radical attached to the aminonitrogen atom. The limitation which prohibits the use of an amine havingmore than three carbon atoms excludes the use of amines having a phenyl,naphthyl, or similar aryl radical, which would decrease or destroy thebasicity of the amine. The term sulfonic acid used in the claims isintended to refer to a substance that consists either of a single acidor mixture of acids.

The new process that I have devised for resolving or breaking petroleumemulsions of the waterin-oil type involves subjecting the emulsion tothe action of a demulsifier consisting of the above described newmaterial or composition of matter. Said material is used either alone,or in admixture with another, or with other conventional demulsifyingagents, and its method of use is the same as that generally employed inresolving or breaking petroleum emulsions of the water-in-oil type witha chemical demulsifier. Briefly stated, the conventional method of usinga chemical demulsifier to break a petroleum emulsion consists inintroducing the demulsifier into the well in which the emulsion isproduced; introducing the demulsifier into a conduit through which theemulsion is flowing; or introducing the demulsifier into a tank in whichthe emulsion is stored. After treatment the emulsion is allowed to standin a quiescent state, usually in a settling tank and usually at atemperature varying from atmospheric temperature to about 200 F., so asto permit the water or brine to separate from the oil, it beingpreferable to keep the temperature low enough to prevent thevolatilization of valuable constituents of the oil. The amount ofdemulsifier that may be required to break the emulsion. may vary from 1part of demulsifier to 500 parts of emulsion, up to 1 part ofdemulsifier to 20,000 or even 30,000 parts of emulsion.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent is:

1. A process for resolving petroleum emulsions of the water-in-oil type,characterized by subjecting the emulsion to the action of a demulsifiercomprising a. water-insoluble salt of a basic alkylamine; said aminebeing characterized by the fact that at least one amino hydrogen atomshas been replaced by a. propyl radical and that said amine is free fromany radical containing more than three carbon atoms; said amine saltbeing obtained from water-soluble, .non-hydrophobe, petroleum sulfonicacid of the green acid type.

2. A process for resolving petroleum emulsions of the water-in-oil type,characterized by subjecting the emulsion to the action of a demulsifiercomprising a water-insoluble salt of monopropylamine; said amine saltbeing obtained from water-soluble, non-hydrophobe, sulfonic acid of thegreen acid type.

3. A process for resolving petroleum emulsions of the water-in-oil type,characterized by subjecting the emulsion to the action of a demulsifiering the emulsion to the action of a demulsifier comprising awater-insoluble salt of tripropylamine; said amine salt being obtainedfrom water-soluble, non-hydrophobe, sulfonic acid of the green acidtype.

MELVIN DE GROOTE.

